Sondershausen (zônˌdərs-houˈzən) [key], commune (1994 pop. 22,370), Thuringia, central Germany, near the western foot of Kyffhäuser Mt. It is an industrial city and a potash-mining center. Manufactures include textiles, clothing, and paper. Nearby are petroleum deposits. From the late 16th cent. until 1918 Sondershausen was the capital of the principality of Schwarzburg-Sondershausen. There is a notable palace (16th–18th cent.) in the city.